Factors affecting temperature reconstruction using stable water isotopes from ice cores on the Prince of Wales Icefield, Ellesmere Island, Nunavut, Canada

The research presented in this dissertation assesses the accuracy of isotopically-derived temperature records from a surface-to-bedrock ice core (LC) drilled on the Prince of Wales (POW) Icefield in 2005. Two primary factors are investigated: 1) the effects of melt on stable water isotope ratios and, 2) the stability of the spatial isotope-temperature slope on the icefield.;The consistency between the spatial and temporal isotope--precipitation-weighted temperature slopes calculated on the POW Icefield serves as a strong indication that interannual to decadal-scale climatic modes do not result in significant degradation of the isotope-temperature relationship in the region and thus do not limit its use as a paleothermometer on relatively short timeframes. A two-source Rayleigh distillation model (RM) is developed to determine the amount of local versus North Atlantic moisture on the icefield. The model estimates that 12% of the accumulation season moisture at the northern summit of the icefield originates locally.;To determine differences in post-depositional processes between two sites on the POW Icefield, modelled delta18O values are generated using RM. Comparison of modelled and measured delta18O values at LC suggests that there is significant degradation of the isotopic signal at the site resulting from the combined influence of melt and wind scour. Because post-depositional modification degrades the seasonal isotopic amplitudes, attempts to date LC using annual layer counting have been unsuccessful. Degradation of the isotopic signal at LC also limits the usefulness of this ice core to serve as a climatic record.;Evaporation that occurs during melt results in the reduction of seasonal isotopic amplitudes and enrichment of average isotopic values. This isotopic enrichment results in the overestimation of temperatures derived from melt-affected ice cores. As part of this analysis, melt-based isotopic correction factors are developed to mitigate the effects of this enrichment and are applied to two melt-affected ice cores from the POW Icefield. Applying the correction factors to the higher-melt site improves the prediction of actual temperatures, reducing the mean annual error from +0.6°C to 0.0°C. No improvement is observed at the lower-melt site.